From nobody Tue Sep 9 21:35:16 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CF40AC678D4 for ; Wed, 1 Mar 2023 20:28:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229718AbjCAU2A (ORCPT ); Wed, 1 Mar 2023 15:28:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229652AbjCAU17 (ORCPT ); Wed, 1 Mar 2023 15:27:59 -0500 Received: from msg-1.mailo.com (msg-1.mailo.com [213.182.54.11]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5CB8AEB7D for ; Wed, 1 Mar 2023 12:27:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=mailo.com; s=mailo; t=1677702473; bh=QgZkwG2KJaskVSRysFIed9zv+7/Cb+p1bNFgkMQ4mcc=; h=X-EA-Auth:Date:From:To:Cc:Subject:Message-ID:MIME-Version: Content-Type; b=kkl6+nMBxZfQJEUfSXyYBFs2usQ/Tvn00Rs9paf84JZpjq/EYSLvjajxrePRJ+W06 tvUrH0IreHuhhg2k/i4pXDRRRZkwKJSHGdxEQdbtb+jgNGNbi7o+8E9H5CwPf9gSjP 7sgBJdc2yA3hUWJFIjpIoIo+rg2aoaQQyJMNVB8E= Received: by b221-2.in.mailobj.net [192.168.90.22] with ESMTP via ip-20.mailobj.net [213.182.54.20] Wed, 1 Mar 2023 21:27:53 +0100 (CET) X-EA-Auth: R7+3+1I5KkV/6Upk1NJ/PVVMvhlx+h3G2Swayr51HNxGFuQWV9jwEpye02f5r0pQ5K+XoAbwT1C0fRkMUOeZSg== Date: Thu, 2 Mar 2023 01:57:48 +0530 From: Deepak R Varma To: Evgeniy Polyakov , linux-kernel@vger.kernel.org Cc: Saurabh Singh Sengar , Praveen Kumar , Deepak R Varma Subject: [PATCH RESEND] w1: Use kfree_sensitive to clear sensitive information Message-ID: MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Replace combination of 'memset(0) + kfree()' by kfree_sensitive() as it prevents compiler from optimizing away from zeroing out memory at the end of a scope. kfree_sensitive() is also safe in case the memory pointer turns out to be null, which simply gets ignored. Issue identified using kfree_sensitive.cocci coccinelle semantic patch. Signed-off-by: Deepak R Varma --- Note: - proposed change is compile tested only. - Resending the patch for review and feedback. Initially sent on Dec 23 = 2022. drivers/w1/w1.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c index 9d199fed9628..0241fc6ca65a 100644 --- a/drivers/w1/w1.c +++ b/drivers/w1/w1.c @@ -73,8 +73,7 @@ static void w1_master_release(struct device *dev) struct w1_master *md =3D dev_to_w1_master(dev); =20 dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name); - memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master)); - kfree(md); + kfree_sensitive(md); } =20 static void w1_slave_release(struct device *dev) @@ -805,9 +804,10 @@ int w1_unref_slave(struct w1_slave *sl) w1_family_notify(BUS_NOTIFY_DEL_DEVICE, sl); device_unregister(&sl->dev); #ifdef DEBUG - memset(sl, 0, sizeof(*sl)); - #endif + kfree_sensitive(sl); + #else kfree(sl); + #endif } atomic_dec(&dev->refcnt); mutex_unlock(&dev->list_mutex); --=20 2.34.1